National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8566, Japan.
Environ Microbiol Rep. 2011 Apr;3(2):144-53. doi: 10.1111/j.1758-2229.2010.00240.x. Epub 2011 Jan 26.
Members of the genus Spiroplasma are actively motile and helical bacteria of the class Mollicutes, which are associated with a variety of arthropods and plants. Some spiroplasmas cause female-biased sex ratios of their host insects as a result of selective death of the male offspring during embryogenesis. Several strains of male-killing spiroplasmas have been successfully transfected into Drosophila melanogaster by haemolymph injection and maintained in laboratory fly stocks. Spiroplasma-Drosophila endosymbiosis represents an ideal model system for analysing the molecular mechanisms underlying host-symbiont interactions. The infection dynamics exhibited by the symbiont within the host, the effects of external and environmental factors on the symbiotic association and symbiont interactions with the host's immune system have been investigated using this system. Comparisons between a male-killing Spiroplasma strain and its non-male-killing variant revealed that, in addition to different male-killing abilities, they also differed in infection dynamics and resistance to host innate immunity. It is currently unclear whether these different phenotypes are interconnected to each other. However, if so, such pleiotropy could facilitate our understanding of the genetic and molecular mechanisms of the endosymbiotic system.
螺原体属的成员是活跃的运动和螺旋形细菌的类柔膜体纲，它们与各种节肢动物和植物有关。一些螺原体导致宿主昆虫的雌性偏性性别比例，这是由于在胚胎发生过程中雄性后代的选择性死亡。一些杀雄螺原体菌株已通过血淋巴注射成功转染到黑腹果蝇中，并在实验室果蝇品系中维持。螺原体-果蝇共生代表了一个理想的模型系统，可用于分析宿主-共生体相互作用的分子机制。已经使用该系统研究了共生体在宿主内的感染动态、外部和环境因素对共生关联的影响以及共生体与宿主免疫系统的相互作用。杀雄螺原体菌株与其非杀雄变体之间的比较表明，除了不同的杀雄能力外，它们在感染动态和对宿主先天免疫的抵抗力方面也有所不同。目前尚不清楚这些不同的表型是否相互关联。然而，如果是这样，这种多效性可以帮助我们理解共生系统的遗传和分子机制。
